As one example of an enclosed electronic apparatus, consider a system for handling baggage in an airport terminal. Such a system incorporates radio frequency identification (RFID) between interrogators and transceivers. In such a system, each baggage tag is an enclosed, battery operated transceiver.
In the field of radio frequency identification (RFID), communication systems have been developed utilizing relatively large packages whose size is on the order of that of a cigarette package or a substantial fraction thereof, and generally speaking, have been fabricated using hybrid circuit fabrication techniques. These relatively large electronic packages have been affixed, for example, to railroad cars to reflect RF signals in order to monitor the location and movement of such cars.
Other smaller passive RFID packages have been developed for applications in the field of transportation, including the tracking of automobiles. These packages include reflective systems of the type produced by Amtech Inc. of Dallas, Tex. However, these reflective passive RFID packages which operate by modulating the impedance of an antenna are inefficient in operation, require large amounts of power to operate, and have a limited data handling capability.
In still other applications of article location and tracking, such as in the postal service or in the field of airline baggage handling and transport, it has not been practical or feasible to use the above relatively large and expensive RFID hybrid packages on smaller articles of transport such as letters, boxed mail shipments or airline luggage. Accordingly, in these latter areas of transport monitoring, as well as many other areas such as inventory control of stored articles, article location and tracking methods have traditionally employed bar code identification and optical character recognition (OCR) techniques which are well known in the art.
Bar code identification and OCR techniques are labor intensive and may, for example, require several airline employees or postal workers to physically manipulate the article and/or the bar code readers to read these bar codes before the transported article reaches its final destination. In addition, the cost of bar code readers and optical character readers is high, limiting the number of locations at which these readers can be used. Furthermore, both bar code readers and optical character readers tend to be highly unreliable.
In yet further and somewhat unrelated fields of: (1) animal tracking and (2) plant tracking, other types of passive RFID tags have been developed by Hughes/IDI/Destron of Irvine, Calif. These tags utilize a coil wrapped around a ferrite core. Such passive RFID tags have a very limited range, on the order of nine (9) inches, have a very limited data handling capability, and are not field programmable. In addition, these tags are limited in data storage capacity and are slow in operation.
In view of the problems described above and related problems that consequently become apparent to those skilled in the applicable arts, the need remains for enclosed electronic apparatus including transceivers wherein the enclosure is inexpensive, readily manufactured in high volume, appropriate in size for use as a stamp, label, or tag, and, in the case of transceivers, operable over distances of several hundred feet without regard for the spacial orientation of the enclosure.